Agricultural combines are large machines that harvest, thresh, separate and clean an agricultural crop. The resulting clean grain is stored in a grain tank located on the combine. The clean grain can then be transported from the grain tank to a truck, grain cart or other receiving bin by an unloading auger.
Rotary combines have one or two large rotors for threshing and separating the harvested crop material. In most rotary combines the rotor or rotors are arranged along the longitudinal axis of the machine. These rotors are provided with an infeed section for receiving harvested crop material, a threshing section for threshing the harvested crop material received from the infeed section and a separating section for freeing grain trapped in the threshed crop material received from the threshing section. Examples are shown in U.S. Pat. Nos. 5,445,563; 5,688,170 and 7,070,498.
It is well known to provide a housing for receiving a threshing and separating rotor with, secured to the inside of the housing, numerous guide vanes or bars which are arranged in a helical configuration. Conventionally, the guide vanes are fixed so that the rate of throughput of crop material can be varied only by changing the speed of rotation of the rotor.
U.S. Pat. No. RE31,257 describes an axial-flow rotary separator of the type which may be used in a combine harvester and in which crop material is propelled downstream in a generally helical path while being processed within a separator housing by use of adjustable internal guide vanes within the separator housing.
Adjusting guide vanes of this type may be used to vary the rate of axial progression of crop material through the separator so as to control the efficiency of threshing and separating. If, for example, excessive losses of grain in discharged straw occur, the crop material feed rate can be reduced by adjustment of the vanes such as, for example, varying the angle of inclination or the pitch of the vanes.
The present inventors have recognized one drawback to adjusting the angle of the vanes is that the vanes conform to a generally curved, cylindrical or oblong, separating section wall or cover. When the angle of the vanes is changed, the vanes no longer closely conform to the curvature of the wall and gaps can occur. Gaps can become clogged with crop material and make operation of the adjustable vanes difficult.
The present inventors have also recognized that angular movement of the adjustable vanes can change the generally cylindrical, curved shape of the separating section cover. This change can significantly change the characteristics of material flow for the section.
The present inventors have recognized that a need exists for providing a adjustable vane system for an axial-flow, rotary combine housing that could be easily and effectively adjusted and would not adversely affect the operating characteristics of the combine.